Telephone-exchange system



E. E-'CLEMENT- TELEPHONE EXCHANGE SYSTEM.

Patented May 16,1922.

4 HEETS-SHEET I.

Inventor APPLICATKON FILED MAR. I4, 1905.

E.E.CLEMENT.I

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED. MAR. 14, 1905.

Patented May 16, 1922.

4- SHEETS-SHEET 2.

Witnesses 5 inventar v E. E, CLEMENT. TELEPHONE'EXCHANGE SYSTEM.

APPLICATION FILED MAR- I4, 1905.

Patented May 16, 1922.

4 SHEETS-SHEET 3.

Witnesses anomep.

UNITED STATES PATENT OFFICE.

EDWARD E. CLEMENT, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR, IB'Y MESNE ASSIGNMENTS, T JAMES R. GARFIELD, TRUSTEE, OF CLEVELAND,

OLE-1T0.

Application filed March 14, 1905.

To aZZ "who 122 it may concern:

Be it known that I, EDWARD E. CLEMENT, citizen of the United States, residing at l l ashington, in the District of Columbia, 5 have invented a certain new and useful Imprm'ementin Telephone-Exchange Systems, or which the following is a specification, reference being had therein to the accompanyimg; d 'awing.

My invention relates to telephone exchange systems, being applicable also to telegraph and other systems of analogous natui it has for its object the provision of means for the interconnection of sub scribers or other lines with apparatus and circuits com posed in part of what are known as manual devices, and in part of what are lrioirn as automatic devices; or in other words the object to combine the best known features oi manual and automatic apparatus and methods so as to eliminate the defects of each and retain the benefits of both. obtaining in addition considerable economies both in installation and in operation as a directresult of the combination.

T he present application is in part a division of 1 s former application filed Septemher it 1904, Serial No. 225,058, for telephone systems and apparatus and method of iiipe ting the same. The invention herein set torth is in the nature of an improvement on the systems patented. to me lipril 3, 1900. by Letters Patent, M507 5 and ($16,677.

The present s' stein embodies the best teatures oi modern common battery manual 6X- change systems, and also the best features at present known. of the standard automatic exchange apparatus known as the Strowger siflerable number o't new features, and have solved a considerable number of problems in rilecting the combination desired.

in my .in'iproved system i divide the work K hi-ee parts, giving the first sub er, the second part to an and the third part a machine.

Jers station i provide any lwown ty e ot common hathone, with two-line bindingposts in posts, one of which is a ground po itn the telephone, and connected to if. oindin )0 ts I provide compact maize and bre nal appar capable in addition, I have embodied a con- TELEPHONE-EXCI-IANGE SYSTEM.

Serial No. 250,055.

of sending four numbers or more, using both sides oi the line and ground in order to facilitate transmission. I employ impulse transmitters which have been described in my own patents above referred to, in Patent 757,030, granted April 12,1904, to E. A. Feller, and others. I shall therefore not describe all the mechanical details of the impulse transmitter I employ, this forming no direct part or the present invention, except in combination with other features. From a subscribers station a pair of linewires pass to the central office, being there nor= mally connected through the contacts of a cut-off relay with a standard form of linesignal-controlling-magnet and battery. The subscribers ringer may be either in a ground tap with a condenser, or it may be bridged when the hook is down. On party-lines the ringers may be either connected from opposite sides to ground, or they may be bridged in either case with or without condensers.

The central otlice end of each line isnormally disconnected from the outside part of the line at the cut-off relay, but is connected permanently to an answering-jack on the manual switch-board,.with which is associatcd the line-signal referred to and also to multiple terminals in the banks of the auto: matic switches. In addition to these terminals, each. line may have further multiple jacks or terminals, on other manual switchboards, to increase the flexibility of the system.

Cooperating with the answering-jacks on the manual or answering switch-boad sections, I locate pairs of plugs, with connecting cords, and I bridge the main battery across'each pair of cord conductors between the windings of a pair of signal-receiving relays. From each manual switchboarr trunk-lines lead to automatic connectors, these being in groups and each group containing the multiple terminals of subscribers lines. On the switchboards these trunk-lines terminate in jacks and the trunks are multipled to all the switchboard sections so that all the trunks in the exchange can be reached by any operator. Each trunk-jack has associated with it a busy signal such as a lamp, and whenever a connection is made through one of the trunks by plugging into its jack at any switchboard section, its busy signals are at once lighted over its multiple jacks at all the sections. Each trunk line at the switch end has a pair of bridged magnets with battery between them. These magnets are controlled over the cord-circuit and trunk from the calling subscribers station (or from a repeater inthe operators cord-circuit) and the magnets in turn control the automatic switch to select the line wanted, one relay controlling the vertical magnet oi? the switch, the other controlling the rotary magnet of the switch, and both together jointly controlling the release magnet, the test and other mechanism.

The operation of the system in brief is as follows :-A calling subscriber sets his number-wheels to form a desired number and takes down his receiver- This closes the linesign'a'l' relay at central and lights the linelamp. The operator at the switchboard, perceiving this signal, inserts an answeringplug'in the answering-jack, thus bringing the bridged relays oi the correspoi'iding cordcircuit i'nto connection with. the line, and also bridging the main battery at the same time. bridged across the connective terminal, but is preferably connected to an extra contact in the line-jack and to extra bank contacts in the multiple switches to be described. Hence, when connection is made with the line either through the jack or through a connector switch,- a local circuit is ClOS6(l through the cut-off relay to energize the same, whereupon it cuts oil the line from the line relay and battery, and puts it onto the jack and multiple terminals.

Thereupon the subscribers apparatus gets current through the cord, the signal-wheels are tripped by a suitable detent-magnet put in circuit when they are set, and the first signal n'uinbers come into central, affecting the bridging relays in the cord, which set a number-signal showing preferably the first two digits of the line-number wanted, corresponding of course to the group-nnmber of the connector-trunk. In other words, suppose the subscriber has set up the number 4468. When the operator plugs in, her cord indicator turns at once to 44 and she therefore puts the second plug into a ack of number ai-group. Thereupon the subscribers number-wheels send the last two digits over the cord and over the trunk to affect the bridged relays of the switch, this being thereby stepped up and around to the desired contact, which is then tested to ascertain if it is busy. The test is accomplished in this way: When the switch is down or in normal position it mechanically closes a circuit-closer which is then held by a magnetically controlled latch. This circuit closer when closed breaks both sides of the trunk- The cut-off relay of the line may becircuit between the controlling relays and the switch, cuts off the ringing relay (or both ringing relays if selective apparatus is employed), cuts off the release-magnet from the trunk-relays, bridges a test magnet across the wiper-terminals of the switch and puts the release-magnet under control of the test-magnet. At the same time it gives control of its own trippingmagnet to the trunk-relays jointly.

Now suppose the wiper to have come on the desired terminals. If the line is idle there will be no bridged battery on it at the central office end, hence the test relay of the switch will get no current, and the switch will therefore remain in contact with that line. In ringing (as will be hereafter stated) one of the trunkrelays is up and the other back, or at this juncture both may be back; this closes the circuit of the trip-magnet which unlatches the above-mentioned circuit-closer with the following results: the. test relay is cut off, the continuity of the trunk is restored subject to the ringing relays, the trip-ma'gnet is cut off and the release-magnet of the switch is put back under control of the trunk-relays. Ringing then proceeds as I will trace later.

If on the other hand the line wanted is busy, the test-relay will get current as soon as the wiper-terminals come on that line contact (the trunk relays being suitably energized at the same time) the release-magnet is then energiy'ed, the switch is returned to normal position, and buzzer or other suitable current is sent back to the calling subscribers station to indicate to him that the line wanted is busy. He then hangs up his receiver, giving a clearing-out signal to the switch-board operator, who pulls the plugs, whereupon all parts are again in their normal condition of disuse.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a diagram of a subscribers sub-station apparatus; Figure 2 is a similar diagram made to appear as an extension of Figure 1, and showing the exchange end of the subscribers line, and an operators cord-circuit; Figure 3 is a similar extension, diagram showing the trunk extending from the operators position to an automatic switch. Figure 3 is a plan View of the contact bank 01" the switch in Figure 3. Figure l is a face view of a switchboard employin my invention; and Fig. 5 is a plan View or a portion of the operators key shelf thereof.

Referring to Figure 1, I have shown the line-wires 1 and 2 passing from the central oliice to the subscribers station A. This comprises the usual transmitter T, receiver T, switch-hook H, ringer Q and a signal transmitting device comprising a series of wheels with cooperating contacts, controlling magnets and a push-button for ringing.

This signalling apparatus is preferably housed in a small casing separate from the telephone, with which it is connected by the Wires 3, l and 5, a ground wire being added which is common to both the ringer and the signal boX. I do not fully illustrate the latter, and except for its cooperation with the other parts it directly forms no portion of the present invention. When unset, the nal box has the circuits of all its wheels open, and maintains the talking circuit 1--23 closed at the contacts co w, which are normally maintained closed by a cam 10 on the wheel shaft 10 There are four wheels w, w w? and 10 giving the necessary four digits to transmit numbers up to 9999; but it is possible to increase the number otl wheels for a larger number of exchange lines. I have indicated these as mounted in pairs on the two shafts i0 and 20 each driven by its own spring and each titted with terminal cam w or @0 Each shaft is geared to a train and is restrained when set by a magnet N or W, the "former in ground wire 8 and the latter in a. similar ground wire 9 from their respective shafts or wheels, to a common ground. Each wncel has peripheral teeth, the two wheels of each L ...1 pan p1 elei ably having their teeth staggered with relation to each other. The cam on the end of the shaft 10 closes together the contacts Q0 and to when its train is run down, so as to cut in the succeeding train and u'iagnet. The four wheels are separately movable to set them so as to form any desired number, as will be readily understood by those skilled in the art. As I have shown them they are in pairs, the first pair held when set by a detent on the armature of magnet VI, whose circuit is closed when they are set. These two wheels transmit thousands and hundrec s, or the number of a trunk group, as will appear later. The other two wheels, i0 -w transmit tens and units, or the number of a line in the automatic switch banks. This pair is held when set by a detent on the armature of magnet W. Both magnets hold their trains until released from central, the second mag ct ll requiring a make and a break do this, the detents on its armature constituting a twostep escapement.

At the central ofiice the line wires 1 and 2 are connected to the springs m and m respectively, of the cut-oil relay M. These two springs are normally in contact with the springs m and m connected respectively by wires 15 and 1:2 to the line relay L and battery, and by the wire 21 to a balancing coil L and battery. The relay L controls contacts in the local circuit ll-12--26-2-T 28-ground, containing the line signal lamp L. W hen the relay M is energized the relay L is cut oil', and the line momentarily broken, atterwhich the springs m' and m are in contact with the springs m and m, connected respectively by wires 14; and 22 and extensions 15 16 to the jack springs J J also by extensions 2930 to the multiple terminals el -W, etc., in automatic switch banks. It will be observed that the spring-jack d and the multiple ter minals are therefore disconnected from the line when the latter is in a condition of disuse. They can only be cut on when the relay M is energized. When energized it disconnects the line l-2 from the signal relay and battery and connects it to the jaclr and to the multiple terminals.

Referring now to Figures 2 and 3, which represent the exchange end of a line, and the circuits and apparatus oi an operators cord, with the terminals of a trunk line, P and P are the operators plugs, or at least one pair oi them, connected by the cord conductors 3335, B l-#36. Each side of the cord circuit is separated by the condenser C or G into two parts, connected through the condensers inductively. The purpose of this separation is to give con trol of the lines from the connensers back, to the calling subscriber direct, and from the condenser forward to the same subscriber indirectly during calling and to the called subscriber directly after connection is made. This will appear more fully later. The cord relays V and R respond to iinpulses from the subs fibers station and re peat these impulses to the trunk lines on the opposite of the condensers.

Relay V is connected from the cord conductor 33 by wires 8C '-38 39 to the battery bus-bar 11 connected to main battery 13. By reference to Figures 2 and 3 it will be observed that l have shown the trunks supplied from one battery and the incomlines and the cord circuits from another. This gives one battery for calling subscribers as such and the other for called subscribers such, which in many cases is desirable. Moreover, where the calling subscriber is located in one exchange and the called subscriber is located in another it imperative not to depend upon one source-of energy to supply both ends of the long line. In the present case I provide for this contingency perfectly, while leaving the continuity of the througn line for. telephonic currents undisturbed.

Relay R is connected by w' es iO-d l from the cord-conductor Z'l-flto ie battery bus 10. Bridged "cross the bus-wiresli') and ii. the main battery B grounded at its middle point so as to give two batteries of equal or. approximately equal potential tor the two sides of line using a ground return. The arrangement described bridges the relays V and ll across the calling end of the cord, 33- with the battery B, and also gires each relay a path to ground through.

one side of the battery. The relay V, I shall call for convenience the vertical relay, and the relay li, shall call the rotary relay, designating the two sides of line l3357, and 2 34-58, in the same way. This is because the relay V ultimately controls the vertical. magnet oi? the automatic switch, while the relay R controls its rotary magnet. Both these relay together control otherthings. The armature v controls the springs o, e e W, '0 r, all of which are normally open except the last, which is closed on wire 4:3 to the corresponding spring of relay ll. The latter relay through its armature r sin'iilarly controls the springs 7", r, r, r, 9-, r, all of which are normally open except the last.

In addition to the vertical and rotary relays, 1 provide a pilot relay N which cooperates with the other relays in the control of the various pieces oi apparatus. The plug P has three contacts, p, p, 39 The last two form the terminals of the main talking conductors ea, 35, 36, but the sleeve 72 is connected to an independent or third conductor (it. This sleeve cooperates with sleeve J or. the trunk-jacks to close local circuits.

Associated with each cord-circuit and pair of plugs is an indicator ii -1 comprising two magnets in separate local circuits 6% and 65, for convenience provided with a common ground return 66. The wire passes to the spring N, and thence to the spring N o'l the pilot relay N, and thence to the spring 42 ot' the vertical relay V. lVhen the latter is energized the spring o is closed against o. and battery current is supplied through the wire 49 by the path traced to the magnet F. The wire (i l from magnet F passes to the sprin N oi relay N, thence by spring N to spi g r or rotary relay E, and when the latter is energized to the battery wire 4-2, the relay R thus controllingmagnet 13, while the relay V controls the magnet F. Obviously these connections may be reversed so that each relay will control the other magnet. The magnet F controls a pawl 7' which meshes with a ratchet wheel 7 connected to the wheel 7' which carries numbers. Similarly the magnet F controls a pawl f meshing with a ratchet wheel i connected with a number-wheel f. A common retaining pawl (not shown) meshes with both ratchets and remains in mesh until both armatures are released and remain back for a dfini'te length oi time. Thus each magnet may step around its wheel separately, and both wheels will be retained in the pOSlillOllS to which they are set until the magnet circuits broken, when a spring or other means 7" on the shaft 7, and

the connecting shat" will restore the same to zero. Indicators oi this general character are well known in the art, and detailed de scription or illustration is therefore unnecessary, particularly as my own type of indicator which I use forms no essential part 01" the present invention. Any equivalent indicator may be substituted in this system, its function being to show the operator the thousands and hundreds digits, or the trunk number, oi the switch trunk which is wanted.

Associated with the cord-circuit is a clearing out lamp L This lamp is jointly controlled by the vertical and rotary relays and the pilot relay N. In order that the lamp may light, both relays V and R must be deenergized, and the pilot relay must be energized. The latter condition only occurs when the plug 1 is in a trunk jack, the circuit 61 being then continued through the sleeve p of the plug to the thimble J ot' the trunk jack, by wire 59 to the relay L of the busy trunk lamps L" and L and by wire 68 to the battery. It will be understood that while I have shown grounds for the return current from these various pieces oi apparatus, this is for convenience oil? illustrr tion only. All battery connections may be solid wires if desired or necessary.

Immediately upon the insertion of the plug 1 the relays N and L get current and pull up their armatures, and the lamps L and L light to show that the trunk is busy to operators at other sections. Here again I may reverse the connections and have the lamps normally lighted when the trunks are idle, putting them out for busy trunks, by relays or otherwise. The arrangement I show is preferable however.

When the pilot relay N is energized by the insertion of the plug P in a trunk jack, it cuts off the indicator E F, and momentarily breaks the battery connection through wires 88 and 39 to the cord conductor 33, at the contacts it -N immediately making it again at the contacts N N The purpose of this is to let the second half oi the sub scribers signal come in.

In addition to the above features I provide a busy bacl: signal connection and relay for each cord. For this I use a special generator G, of any preferred type giving current which will create a characteristic sound in the calling subscribers receiver to apprise him that the wanted line is busy, and the "frequency of change in this current should be such with relation to the constants of the relays V and B, and VR (Fig. 3) that it will not leak back on the main battery wires. The bus-wires 5758 are connected through contacts e and e to wires 53*5 l and so to the cord conductors STE-34.

This current is put on by the busy relay E, whose armature 6 when attracted closes the contact 6 which closes the circuit of the magnet 0*. This magnet c connected to wire 33 by the wire 53 when its armature e is attracted. This relay 6 is in parallel with the relay V one terminal ot each being connected to the bus-bar ll. of battery B. This relay will continue to hold up its armatures so long as the calling subscriber has his telcphone renjioved from thehook. Across the armatures c and e a generator or interrupting machine is connected by the wires 57' and 58'. The contact 0" is connected by the wire 54s to the wire 34h This bridges current from the generator across the strands 33 and 3 and the current will in turn be transmitted through the line wires 1 and 2 to the subscribers telephone. This busy signal will continue until the subscriber hangs up his telephone and tie-energizes the magnet 6 whose armatures e and a will fall back and disconnect'the generator current. a

The magnet E which controls the busy back, is sluggish in its action, and. has two differential windings e and a put on the core end to end, so that for battery current passing through the windings serially the magnet is neutral; for battery current passing through the windings in parallel, that is in the same direction, the magnet is active; but for voice currents the windings are impassible, and neither winding by itself will pull up the armature. These two windings are connected in a bridge across the conductors 35%36, which may be traced as follows: 35,47,6', as, o ,o*,4l, l5,'/ ,r i-9, 6,4:8, as. This is grounded at its middle point between the contacts a and r ot'the relays V and R. In the normal forward transmission of signals the impulses caused by either relay do not affect the magnet E, which serves then merely as an impedance to prevent the shunting of voice currents, ii any. After the connection is completed the magnet remains bridged until. clearing out, but if the line wanted is busy current comes back over both sides of the trunk 5758 in parallel, the magnet E is energized, and the busy back signal is given.

The generator G may be common to the entire exchange.

Passing now to Figure 3, I have therein shown the circuits, and indicated the appasubscribers line in that hundred is multi-I pled. The five multiple terminals jj*j etc, of line l-2 in Figure 2 are supposed to appear in the banks of the five switches as signed to the hundred group inwhich the line belongs It the number of this line be f r ins a c 4 6 ,;i ip es w l pp in the banks of five switches all numbered 44. From these five switches five trunk lines are led to the manual switchboard shown in Figure 4 and are there connectedto the trunk 'iacks J in each of the separate positions, so

separately for some purposes and jointly forothers. The magnets V and R are bridged across the trunk circuit 57-58, with the main battery B by a path traceable as tollows: 577a-V95y"g 77, battery Z)b79R'7858. Itwill be observed that the connection of V with the conductor 95 is by way ofcontacts controlled by the relay Y, this being the test relay. Vhen this relay is energized the magnet V is taken off the wire 77 leading to the battery bus-wire 10 and is put on the other battery wires 113, 11 thus placing the portion 1) of the battery 13 to both sides of line through both relays V and B. This is for sending the busy back signal that I have mentioned in connection with relay E in Figure 2, the

current so sent energizing that relay to put.

the generatorG on, the calling line. The sending back of current in this way is only momentary so far as the test relay Y is concerned, but the generatorC stays on the line until the subscriber hangs up.

The relay V controls a magnet V through the springs '12 01 closed together to put battery on the magnet when the relay is energized. Relay R controls magnet R in the same way through springs r rt. These two magnets are the vertical and rotary magnets of the switch, respectively.

They have a common return wire 83 which passes through normally closed contacts on the pilot or latch switch X, and to magnet wires 82 and .82, whereby they are cut off after the desired connection is obtained. Here, as in the cord circuit of Figure 2, the local controlling magnets for the signal are of no use after their function is performed and a pilot switch of some kind is the proper thing to cut them off and leave the line relays V and R or V and R thereafter to control the testing, ringing and clearing out. It is by this successive manipulation of the local circuits that I am enabled to employ the same bridged relays V, V R, R, for so many d ferent pur oses, The .pilotswitch X is an ag 'regation of contact springs with platinum c dntact points, as all the switches and relay contacts are supposed to be herein,

in accordance with the best practice at this a, which carries the ends of the long springs m m, m m1 and When down this switch makes the following connections and disconnections: 1st, the wires 72-.73 lead- 'ing to the wiper contacts 3 and a are disconnected from the wires 7l ot the trunk, and are connected to the wires 91 and 89 leading to the test relay Y through con tacts 7c'-7c on relay K, so that the relay K 'must be de-energizedit the test relay is to act. 2d, the vertical and rotary magnets V and B have their clrcuits completed through springs x -a2 m 3d, the release magnet Z is disconnected from its normal terminals 12 and 1 of relays V and R, and connected to battery wire 177 on one side and to-spring 2 of test relay Y on the other. 4th, the latch magnet X of the pilot switch itself is given control of all these connections because the switch is held down by a latch engaged by the armature or the magnet. X and released when the latter is sulficiently energized. I say sul'liciently energized because this magnet is sluggish, tor a purpose which will appear in the statement oi? operation.

The pilot switch X is forced down to the latched position shown in Figure 3, by any suitable part of the mechanical switch mech anism in its return to normal after connec tion. In the figure I have indicated this as 'an arm on the main spindle of the switch,

which strikes the bar a; in descending and forces the springs down into the position shown, where they are held by the latch controlled by magnet X;

When magnet X is energized to release the switch 31, the following connections and disconnections are made: 1st. wires 72 and '73 are disconnected from the testrelay and are continued to wires 70 and 71, by way of the contacts 70", it, k and k of relay K, this being a ringing relay which breaks the line back when ringing forward. 2d, the vertical and rotary magnets V and B have their circuits broken at contacts m a9 .r 3rd, the release magnet Z again connected to the contacts r and e of relays V and B,

being disconnected from the contacts of the test relay. Atth, the latch magnet is left idle without further control of the pilot switch, which remains up with the, lastconnections intact until the end of the connection and the return of the main switch to normal or zero position.

The ringing relay K is controlled by the relay V, in the following way: Relay K i sc'onnected on one side to a back contact '22 of relay V, and on the other side to the wiper S in order to energize relay K it is necessary that relay V be energized and the relay It be rile-energized simultaneously, and the wiper S resting on the contact leading to the line cut-Off relay M. It will be seen that cut-off relay M is energized through the winding of the ringing relay K, the energizing circuit being from battery 13 through 79', r", 7', 8O, c if, K, S9, 8, J, 30, M, 12, 10, B and ground. This relay is cut off after ringing, and to provide 1 r means to continue to energize the relay A a resistance coil B is connected to the wiper S in multiple with the relay K. This resistance coil, as will be seen, is connected permanently to both the wiper and battery and. so cannot be cut 01? in any way. The calling subscriber rings in the following way:

The wheel 10 in the transmitting device, is-

provided with a long make contact which grounds the line 1 over which the relay V is controlled. This ground is of long enough duration to hold up the armature of relay V until the ringing relay K can connect generator current across the called line. While this long contact is made by the number-wheel 10 the opposite side oi the line No. 2 is broken by the number-wheel "/0 This in turn (lG-QUGLgiZQS the relay 1% which is necessary to operate the ringing relay H. The subscriber is provided with a pusl1-button P for ringing again, it necessary. This button P grounds No. 1 side of line and opens No. 2 side of line just the same at the number-wheels v0 and 10 and the calling subscriber can ring as many times as he desires.

Before proceeding to the statement of operation 1 shall refer to some additional mat ters which are of importance in the system but which have been omitted from the illustration for the sake of simplicity. Refer ring to Figure 2, it will be recalled that I described the trunk jacks as being arranged in groups, those of each group connected to automatic switches containing multiple terminals of the same lines. l. have also described the number of such group. when one of its switches i wanted, as being designated to the operator by the indicator FF.

In Figure 2 I have shown a pair of plugs P P united by cord conductors 300-350, 340360, intended to cooperate with the jack terminals of the subscribers lines to connect the same at will with other subscribers or with trnnk lines leading to the chief operator, to a special manual operator. to long distance. or the like. In order to call for this service a subscriber according to my system need not set his impulse transmitter at all, but simply works his hook up and dowmwhich by opening and closing his line circuit rapidly, causes his line lamp L to flash. Upon perceiving a flashing lamp,

the operator inserts a plug P and puts the and who can give him connection, receive his complaints and the like, the same as in any manual system now existing. It a subscribers transmitting apparatus is out of order, or for any reason he fails to obtain a desired connection, he can always get an. operator to whom he can complain, and who can give him an emergency connection. For this purposeil provide the manual operators in the exchange, including; the long distance and toll-board operators, etc, with a set of trunks leading to automatic switches uniform with'the others and containing subscribers multiple-terminals The operation of my system thus described is as follows: Suppose subscriber A desires to call. another subscriber whoml will designate as 8753. Subscriber .ti firstsets his four number-wheels in, 71), in and wa and takes down his receiver. fie gets no current as yet in the latter, the talking circuit heiu open after he sets his wheels. The wheels '1 0 -w are cut out, with their magnets, at the springs Q0 w and as the magnet requires amake and break to release its wheels the latter remain set. The magnet on the other hand gets current as soon as its wheels are set, by the following circuit: main battery 7), 1021, balancing coil L m m 2, l1, 10 to, (the armature being mechanically advanced into attracted position by the finger W on the shaft) W, 8, 10*, ground, and back to bat tery. This current energizes magnet i l, holds the wheels set. The subscriber then taking down his telephone energizes the line-relay L and lights lamp L.

7 The cordconductors are then connected through the jack of the respective line, wires, and at the same time the extra contacts on the jack close the third wire local circuit to the cut off relay i l, which pulls up its armature m and m The magnets L and L are thus cut oil, and the wires 1-2 are continued through springs m and m to the jack p g 5', 7

In connecting the line through to the jacli, it was momentarily broLen at springs m m hence current was out off from magnet W, which may control its own ircuit so as to stay cut off, or whose armature may be mechanically trapped in any well known manner so that it will notagain engage the wheel after releasing it. The two wheels '10 and w now start to revolve, and each makes,

and. breaks its own side of line a number of times corresponding to its setting, in this case 8 and 7, respectively. These impulses go in alternately, because although the line m g t be cl sed at in erva s Wi o lam-age,

bridged by it l do not care to have both sides open at once until the signal is and noted, although even this would be no drawback it the mag nets l and F be made sluggish as regards the full. retraction of? their armatures. The impulses coming in over the vertical and rotary sides oi line affect the relays i and ll to set the signals F-F to 87. This action is almost instantaneous, and the operator noting the number, takes up the companion plug P and inserts it in a trunk aclr of the group bearing that number in some one of the panels T before her o her right or left hand neighbor in, the same section. The insertion of this plug closes the following circnit locally: batte y I) (Figure 3), (58, L 69, J 39 (Figure 2), 61, N, 62 and through ground hack to battery. The relay N then pulls up, disconnects the signal magnets J-Ji", and momentarily breaks the circuit through wires 33 39 which is the holding circuit of the substation magnet ll and which was initially closed when the first two wheels 7 and Q0 ran down. The momentary break in the holding; circuit of the magnet allows the right hand armature oi" said magnet to be retracted and. release the wheels co 10 and. as the plug P is then in the trunk jack, these wheels now send their impulses on over the trunk. In the present case T have included condensers C in the cord circuit, in order to separate the battery feed, and inasmuch as the relays V-R respond to all impulses anyhow, l employ them tor repeating by causing them to ground the two sides of the cord conductors 25-36 they worlr. in the branch from each side is included one winding; of the relay E. 7

Referring now to Figure 3, the number 53 comes over the two wires the relay V gets live impulses. and the relay R three. These alternately make and bre l; the local circuits of the vertical and rotary magnets V R whereby the switch terminals a s are set upon the contact of the line wanted. (lrdinarily, that is when. it is any other line than his own. the calling; subscribers wheels then leave the circuit open or closed for a brief time, during which the relay Y remains elf across the we med line t erminals. This time is long eno i to permit the relay to be effectively ener ed if the line is busy and ha ba it. the rel v being; snfhi' I V .7 that it w ll not respond to purely 1nomenta ily impulses as the wipers s and s pass over the conta ts oi" lines not wanted, to reach the contacts of the line wanted. lt that line is idle. these terminals are disconnected as shown in Figure l, and therefore the relay Y gets no current. The last number-wheel in running down places a passing ground on, line wire No. l. This occurs as the last impulse comes in. The same thing is accomplished by the subscriber pushing the button. The immediate effect of this is to pass current through the relay V which grounds the conductor 35 causing current to pass through relay V which attracts its armature and. the circuit of the ringing relay K is then completed. This relay pulls up its armature connecting the generator G to the springs 7.2", k" and also closes the on cuit of the latch magnet X, which pulls up its armature and releases the pilot switch. X. This rises. cuts off the vertical. and rotary magnets V connects the *ire 73 from the wiper terminal 8 to the s1 ring a and generator. it also connects the wire 72 from the wiper terminal 8 to the spring 1 0 and generator, disconnects the test relay and puts the release magnet under the joint control. of the relays V and R. It will be observed that as soon as the pilot switch X has operated the wires and 72, 71 and 73 are continuous. hence battery current will pass forward. over the called subscribers line, the cut-off relay M being energized disconnecting the line-signal apparatus and connecting the line straight through. Now suppose the line wanted was busy when the connection was first effected, the grounding of one side of the line by the subscriber and the working of the relay K, whereby the latch magnet is actuated has not yet occurred. The test relay is energized, and separates its contacts y y and closes together its contacts y y and 4 when bridged across a busy line. Such a line will be supplied with current through the windings of relays V and ll if it is a calling line or through the windings of the rel ys V and R if it is a called line. The relay magnet V is thus taken off of battery wire 77 and is put on the battery wire 113, the same side as the relay magnet R. Current then flows from the side I) of battery through these magnets in parallel back through the trunk line wires in parallel, through the branches ll-e6 and 4lS-ei 9 in 'warallel and through the closed contacts of, w and r. M in parallel and to ground, passing the windings c, 0. also in parallel and energizing the relay l). This attracts its armatures, closes the contact and c which in turn closes the circuit of the busy back generator, which remains closed until the calling subscriber hangs up.

At the same time the test relay Y closes the circuit of the release magnet Z which restores the switch to its normal position and clears the trunk. The relay V is then put back on its proper side of battery for the next call.

The structure of the switch of Figure 3 needs no detail description, as it involves the usual vertical and rotary ratchets for the spindle S, cooperating with pawls controlled by the vertical magnet V and the rotary magnet R which in turn are controlled by the vertical and rotary relays V and R respectively. In order that the wipers may have free movement over the contacts, they engage the ends thereof instead of the sides as in some other forms of switch. This is diagrammatically shown in Figure 3 and it should be remarked that the wipers while shown as of flat spring metal may of course be varied as to their form and arrangement, the only requirement being that they shall preserve their alignment with respect to the spindle, and at the same time maintain pressure of their tips against the inner ends of their bank contacts. Subject to this change in the method of effecting contact, standard types of switch may be employed. This simultaneously operating two-way switch is shown in my former application Serial No. 225,058, of which the present application is in part a division.

Having described my invention, what I claim is:

1. In a telephone exchange system, subscribers lines having terminal line signals at the central office, a centralized source of current supply therefor also at the central oilice, and means at the subscribers stations to determine the flow of current therefrom in the lines, automatic switching apparatus at the central office adapted to effect connection with the lines, means controlled by an operator for connecting a calling line with the automatic switching apparatus, magnetic controlling means for said switching apparatus and connections therefrom to said centralized source, together with means at the subscribers station for controlling cur rent flow from said source through said magnetic controlling means for the purpose of setting said switching apparatus to select a wanted line, means in said switching apparatus for testing the selected line to ascertain if it be already engaged, and means dependent upon the result of said test for maintaining talking circuit continuity between the calling and the wanted subscribers lines, substantially as described.

2. Connecting means for telephone systems consisting of answering terminals and a series of switching or connecting terminals, a certain number of subscribers lines being connected with their answering terminals in one group, and a certain number of lines being connected to the switching or connecting terminals in one group, of trunk lines leading from each group of answering terminals to the various groups of switching terminals, automatic switching apparatus connected with each trunk-line and adapted to co-operate with one group of switching or connecting terminals, together with means under the control of an operator to connect an answering terminal in her group with a trunk leading to any desired switching apparatusand group of connect- Cir devices ada we riapparatus connected with each trunk-line and adapted to co-operate with one group of switching or connecting terminals, together with means under the control of an operator to connect an answering terminal .in her group with a trunk leading to any desired switching apparatus and group of connecting terminals, a source of current common to a plurality of the lines and trunks and supplying them with energyboth for talking and signaling, and further means whereby current from said source may be controlled through the trunks by the calling subscriber for the operation of the automatic switch, substantially as described, at in telephoneexchange system, a

switchboard, subscribers lines provided with terminals upon said switchboard, a number signal registering device and an automatic connecting means adapted to be successively placed, by an operator, under control of a subscriber in response to asignal, substan tially as described.

5. ln atelephone system, a central office, subscribers lines radiating therefrom, each provided, at the subscribefis station, with a norn'ially-open selective transmitting-circuit, and a normally-closed signal-receiving circuit, and at the central oflice with a normally-closed calling signal-circuit; means whereby the subscriber may close his selective signal-circuit, and thereby operate the ccntral oflice signal, cord circuits for interconnecting the lines, cord circuit signals and automatic connecting devices at the central oliice adapted to be operatively connected to the suhscribei"s line while disconnecting the central oliice calling signal therefrom, and clearing out means tor the automatic p ed to be controlled by the subscribers, substantially as described.

lipln a telephone system, a subscribers provided at the subscribers station,

phonic apparatus normally disconierejirom, a signal receiving device ,aliy connected thereto, an impulse 'urusinitter and a magnet controlling the nine, in a circuit normally broken at said a emitter, a signal for the line at the ceniie, a magnet for controlling the same,

and a battery, both normally connected to the line, the battery current being of a proper character to operate the signal-magnet, and also the transmitter-magnet at the line wires while disconnecting the signal magnet therefrom, a responsive circuit-controlling device in circuit with said connective means, and suitable connections whereby the condition of current in the line is changed in the act of making connection therewith so that the subscribers transmitter-magnet is operated, and the circuit controlling device affected in response thereto, substantially as described.

7. In a telephone exchange system a switchboard divided into sections, subscribers lines connected to terminals grouped thereon, trunk lines, answering and connecting plugs at each station, each answering plug adapted to be connected to any one of a set of trunks upon different panels,

automatic means connected with the trunk circuits and adapted to be controlled by the subscribers for ellecting final connections, and a number signal device for each answering plug connected to its circuit, and a suitable generator, substantially as described.

, 8, In a telephone exchange system, a series of line and multiple terminals and a series of automatic directively driven connector switches, said multiple terminals being distributed among the banks of the respective switches, the terminals of each line being normally disconnected therefrom, and a cutof? relay for each line controlled in making connection therewith to connect it with said terminals, substantially as described.

9. In a telephone exchange system, sub scribers" lines, answering terminals for manual connection with the lines, automatic switches, connecting terminals distributed in the banks of automatic switches and normally disconnected from the lines, and means controlled through said connecting terminals to connect their line thereto.

10. In a telephone exchange system, subscribers lines, line terminals therefor at a central office normally disconnected from their respective lines and connected to signal devices, automatic switches co-operat ing with said line terminals, means whereby a calling subscriber may control a switch for cii'ecting a connection between his line and another, and means operated through said line terminals and co-operating contacts, of a wanted line to connect it to its said as minals, substantially as described.

11.. In a telephone exchange system, subscribers" lines, automatic connector switches having terminals corresponding to said lines but normally disconnected therefrom, means whereby each switch may be connected temporarily to a calling subscribers line, means in each switch circuit to test the wanted line to ascertain if its terminals are connected or not, that is if it is busy or not, and a relay for each line to connect all its terminals so as to test busy when connection is effected with any of them, substan tially as described.

from. said source through a switch when connection is made with the line to disable the signal, substantially as described.

13. In a telephone exchange system, subscribers lines, answering terminals and .multiple connecting terminals for each line,

the former disposed in answering groups with line-signals, and automatic switches having banks containing the latter, a relay for each line normally disconnecting the multiple terminals therefrom but adapted when connection is made with the line to connect the terminals thereto, and means for actuating the automatic switches adapted to be controlled by calling subscribers, substantially as described.

14:. In a telephone exchange system, subscribers lines, answering terminals and multiple connecting terminals for each line, the former disposed in answering groups with line signals andyautomatic switches having banks containing the latter, a relay for each line normally disconnecting the multiple terminals therefrom but adapted when con nection is made with the line to connect the terminalsgthereto, and means for actuating the automatic switches adapted to be controlled by calling subscribers, through their answering terminals, substantially as de scribed.

The combination with a telephone line having a limb extending to the central ofice, of a plurality of terminals therefor each having a contact, adapted to form a portion of the line circuit and normally insulated from line and from ground, an automatic switch and its circuit having testing apparatus co-operating with said terminals, a relay to connect said normally insulated contacts with the limb of the line when actuated, means to change the electrical condition of said contacts when so connected, a controlling magnet and a battery associated with said switch circuit, and a switch at the subscribers station, whereby when a connection is made, said contacts are charged for the purposes of testing, said terminals are placed in operative relation with the line and said controlling magnet is placed under the control of the subscribers apparatus, substantially as described.

16. The combination with a telephone line of a test-terminal normally disconnected therefrom, a relay for connecting said test terminal with the line, an automatic directively controlled selector switch with testing apparatus, a circuit terminating in said switch, controlling apparatus associated with the switch circuit, a source of electricity also associated with the switch circuit, and means for closing the circuit of said source over the telephone line to operate the said controlling apparatus, and a circuit also through said relay, when connection is made with the line, substantially as described.

17. In a telephone exchange system, the combination with subscribers lines having answering jacks and multiple terminals, of operators cord circuits and automatic switches each containing the multiple ter minals of a certain number of subscribers lines, and means at each subscribers station for actuating and restoring said switches, together with trunk lines leading directly from the several operators positions to the automatic switches, whereby a calling line may be trunked by an operator to the automatic switch containing a terminal of the line wanted, substantially as described.

18. In a telephone exchange system, subscribers lines, trunk lines terminating in l automatic switches and associated through the switches each with the same determinate group of subscribers lines, said switches containing each multipled terminals of the same group of lines, means operable by an operator in response to a call to connect the calling line at one point to any of said switchtrunks, and controlling means for the switch then operable by the subscriber to select and connect with the line of the wanted subscriber at a separate point, substantially as described.

19. In a telephone exchange system, sub scribers lines having answering terminals and multiple terminals, said answering terminals being grouped upon a manual switchboard before operators, and automatic switches with said multiple terminals grouped in their banks, trunk lines leading directly from said automatic switches to said switchboard, and means controlled by the operators at said switchboard to connect any calling line with any of sail trunks and thence to its automatic switch, together with means controlled over the subscribers lines for restoring said automatic switches, substantially as described.

20. In a telephone exchange system, subscribers lines, a manual switchboard having one or more answering panels fitted a calling subscriber to an idle trunk, and actuating means for the trunk switch controlled thereafter from the subscribers sta tion, substantially as described.

21. In a telephone exchange system, subscribers lines and automatic switches, line terminals for said. lines for answering purposes located upon a manual switchboard and multiple terminals for connecting purposes under the control of the automatic switches, said switches being arranged in groups, those in each group containing mul tiple terminals for the same group of subscribers, and all the switches of each group being connected directly by trunk-lines to multiple connecting terminals upon the manual switchboard, together with means under the control of an operator to connect a calling line with the trunk of an idle switch in any desired group, and actuating means for said'switch controlled thereafter from the calling subseribers station, substantially as described;

522. In a telephone exchange system, subscribers lines and automatic switches, line terminals for said lines for answeringpurposes located upon a manual switchboard and multiple terminals tor connecting purposes under the control of the automatic switches, said switches being arranged in groups, those in each group containing multiple terminals for the same subscribers, and all the switches of each group connected by trunlnlines to multiple connecting;- terminals upon the manual switchboard, together with means under the control of an operator to connect a calling line with the trunk ot an idle switch in any desired group, and a busy signal circuit associated with each. multiple-trunkterminal on the switchboard so arranged that when a trunk is in use, that trunk will test or signal busy to all operators until the end of the connection. when it is again-idle, substantially as lGSZl'lllECl.

In a telephone exchange system, subscribers lines. answering-terminals therefor upon a manual switchboard, trunk-lines with automatic switches at one end, and at the other end connective terminals on said switchboard, busy signal associated with each trunk-terminal on the switchboard, and means for displaying all the busy signals corresponding to a particular trunk when connection is made with any terminal thereof. substantially as described.

'24. In a telephone nchange system. sub scribers lines and line terminals theretor,

a series of automatic switches and trunklines connected thereto. with multiple line terminals in the switches and connectiveterminals for the trunks, together with operators c-o-rdcircuits for connecting a callin line with any desired trunk-line giving; direct access to a particular switch and! thereby to its group 0i. subscribers multiple terminals, and subscribers sending and switching; devices for switch control therea? substantiallyas described.

ln telephone exchange system, a subscribers liuerircuit, a cord and plugadapted to be connected therewith when calling, an automatic switch containing multiple terminals of subscribers lines and a trunk-line to: the switch termina ting" in a jack adapted to cooperate with said plug, together with number indicating means at the central station whereby the calling subscriber may info m the operator of the trunk connection desi ed, and means at the subscribers station for controlling the trunk switch thereafter. substantially as described.

26. In a telephone exchange system, a subscribers line and a terminal cord and plug adapted to become connected thereto in calling', a plurality of automatic switches each containing multiple terminals of a plurality of subscribers lines, a trunk line lea ding to each switchn each trunk line terminating in a jaclr. means at the central oilice for desigmating the particular trunk line required, and means at the subscribers station for actuating the same and thereafter for actuat ion the automatic switch connected with that trunk to select the subscriber anted, sub stantially :s described.

27. in a elephone exchange system. a subscribcus station provided with a talking and a signal transmitter, a line circuit therefrom to a central oliice, an operators cord circuit adapted to be connected with the line at the central o'liice in response to a call. plurality oi trunk lines and automatic switches associated therewith, each switch arranged to connection between its trunk line and a plurality of subscribers lines. a indicating; device associated with the operators cord c'cuit and controlling magnets for each switch, whereby calling subscriber may first designate to an operator the trunk connection desired, and thereafter r i \ontrol the automatic switch associated with that trunk to continue the connection ultimatel o the line wanted, substantially as described.

98. Tu. a telcnhoue exchange system. line terminals at a central oilice normally disconnected trom battery. with means to connect battery thereto in makingconnection with the line, an automatic switch provided with controlling magnets and a test magnet,

the former being normally connected so to respond to current over a calling subline, togethe scribers line in making a selection, and the latter normally connected to the switching terminals to be brought into circuit with the terminals ot the wanted subscribers with release magnet con trolled by the test magnet during selection, and thereafter controlled by the calling subscriber, substantially as described.

29. in a telephone exchange system, a two wire subscribcfis line, and two wire connecting circuits, an automatic switch adapted to be controlled by a calling subscriber to make connection with the line oi? a wanted subscriber, controlling magnets for said switch normally energized over the line-circuitand controlled by the calling subscriber, a test magnet normally connected to the switch terminals so as to be brought in circuit with the wanted subsc 'bers line for test, a release magnet primarily controlled by the test-magnet, and means actuated in complcting a connection to disconnect said testmagnet and to place the controlling-magnets under the joint control of the connected subscribers, substantially as described.

30. In a telephone exchange system, controlling magnets, a metallic talking circuit normally severed and having one end connected to said controlling magnets which are adapted to be controlled from a calling station, and having the other end normally connected to a test-magnet for testing the condition of the line wanted, with means to di connect id test-magnet and restore the continuity ot the talking circuit in completing a connection, and ringing means bridged across said metallic circuit, substantially as described.

23.. In an automatic switch, controlling magnets adapted to be controlled from a calling station, a metallic talking circuit normally severed and having one end connected thereto, and having the other end normally connected to a test-magnet for testing the condition of the line wanted, with means to disconnect said test-magnet and restore the continuity ol the talking circuit in completing a connection, and further means becon ing operative upon the restoration of the switch to a condition of disuse to again sever the talking circuit therethrough and to connect the test magnet as before, together with ringing means bridged across said metallic circuit, substantially as described.

32. In an automatic switch, controlling magnet adapted to be controlled from a mal condition of disuse to again sever the talking circuit and connect the test-magnet as be'l'ore, together with ringing moans bridged across said metallic circuit, substantially as described.

An automatic exchange switch proyided with a plurality of subscribers line terminals and a pair ot selective terminals co-operating therewith, a metallic talking circuit through the switch connected to said selective terminals and adapted to be extended back to a calling subscriber, a source of current bridged across said metallic circult and a pair of controlling magnets for the switch includedin said bridge with the battery, an intermediate ground connection the battery, and means at a calling subscribcrs station for controlling the flow of current in' either side of the metallic circuit separately and independently of the other, whereby each controlling magnet may be separately energized, together with a ringing generator, a rin ing relay controlled by one of said magnets and itself determining the connection of the ringin enerator 0 t" to the circuit, substantially as described.

34;. An automatic exchange switch provided with a plurality of subscribers line terminals and a pair of selective terminals co-operating therewith, a metallic talking circuit through the switch connected to said selective terminals and adapted to be ex:- tended back to a calling subscriber, a source oit current bridged across said metallic circuit and a pair of controlling magnets for the switch included in said bridge with the battery, and intermediate ground connection for the battery and means at a calling subscribers station for controlling the flow of current in either side of the metallic circuit separately and independently of the other, whereby each controlling magnet may be separately energized, together with a ringing generator, a ringing relay jointly controlled by said magnets to determine the connection of the ringing generator to the cir cuit, substantially as described.

35. In a telephone exchange system. subscribers metallic circuits, metallic circuit automatic: switches, and metallic connectingcircuits, together with bridged common battery having intermediate ground connection and serving a plurality of: the subscribers lines, and controlling magnets for the several switches connected to the metallic circuits in se'ies with the par s of said battery, together with means at the subscribers stat-ions to determine the joint and separate action of said magnets, substantially as described.

36. In a telephone exchange system, a switch having a pair of wiper contacts relatively movable with regard to subscribers line terminals, a talking circuit extending from said wiper contacts, a pair of conment of said wiper contacts to any desired subscriber s line terminals, connections back from the switch to'a ceiling subscriber, a busy signal normally inoperative with respect to said subscriber, a test relay for the main switch, and a pilot-switch normally connecting the same to the wiper contacts to test a .vanted line, means controlled by said test-relay to connect the busy signal to the calling line it the line wanted is busy, and means to actuate the pilot switch to disconncct th'e test-relay and complete the circuit for conversation when the line wanted is idle, substantially as described.

In atelepho'ne exchange system, sub scribers lines and automatic switches for interconnecting the same, operators plug-circuits for cennecungrhe lines to the switches, and signal repeaters associated with said plug-circuits, together with a signal register operated thereby, substaiitially as described.

38. In a telephone exchangesystem, subscribers lines and automatic switches, operators circuits for connecting the lines to the switches, indicating means associated with the operators circuits and controlled by calling subscribers to designate the switch connection wanted, together with means controlled by an operator in continuing a switch connection to disable the indicator, substantially as described.

39. In a telephone exchange system, subscribers lines, connective circuits and automatic switches associated therewitln a common source of current supply for said lines and switches, means manually controlled by an operator to directly connect and disconnect a calling line with and from an .automatic switch, controlling magnets for the switches, signals associated with the manual connecting means, and means wherebysaid controlling magnets and signals may be actuated by the subscriber whereby the switches will be automatically cleared out and indications given to the operator for taking down the manual connecting means, substantially as described.

40. In a telephone exchange system, subscribers lines, an operators cord-circuit, connective trunks for said lines arranged in groups, automatic visual means connected with the cordcircuit for indicating the trunk leading to the desired line and an automatic switch for effecting connection between the trunk and the desired line.

41. In a telephone exchange system, subscribers lines, an operators cord-circuit, connective trunks for said lines arranged in groups, automatic visual means connected with the cord-circuit for indicating the trunk leading to the desired line and an automatic switch for effecting connection between the trunk and the desired line, said switch being under he contro o he cal i g subsc iber.

42. In a telephone exchange system, subscribers lines provided with a series of signal wheels, an operators cord-circuit, con nective' trunks for said lines, means actuated by the operation of certain of said signal wheels for automatically indicating'to the operator the trunk leading to the desired line, means actuated by other of said wheels for automatically effecting connection of the trunk line withthe desired line. i

43. A telephone system comprising a connector, a manual switchboard provided with an operators connecting-cord, a suitable connection between the connector and the manualaswitchboard, and a busy-release circuit for insuring an automatic release of the connector under certain conditions, said automatic release-circuit including a talking strand of the said connecting-cord.

, 4:4. A telephone system comprising a 85 connector having vertical and rotary motion provided with aplural ity of lineter minals, each terminal comprising a plurality of contacts, and aplurality of relays, a contact of each line-terminal bein permanently grounded through one of said relays.

45. A telephone system comprising a subscribers line, a relay for said line, a connector, and two energizing circuits for said relay, both of said circuits being controlled by said connector.

46. A telephone system comprising a subscribers line, a relay individual to said line. a connector, an operators plug-switch, and three energizing-circuits for said relay, two 100 oi said circuits being controlled by the connector. and the third circuit being controlled by the plug-switch.

47. A telephone system comprising a connector provided with release mecha- 105 nism, and having talking-conductors, and a busy-release-circuit for preventing the connector from interfering with a busy connection, said'circuit including a talkingconductor of the connector.

48. A telephone system comprising an electrica1ly-propelled and step-by-step-actuated switching machine provided with a. plurality of line terminals, means for establishing a guarding potential at any'terminal 115 of a line which is busy, and a busy-release circuit including a talking conductor when the machine attempts to establish connection with a line-terminal having guarding potential, whereby the machine is prevented from 120 establishing connection with a busy lineterminal.

49. In a telephone exchange system, the combination of a subscribers telephone line,

a spring jack for said line, an automatic 1 line, common battery means for supplying current to the line for talking purposes, said spring ack and connector terminal being connected in multiple.

50. In a telephone exchange system, the combination of a subscribers telephone line, a spring jack for said line, an automatic switch provided with voice-current conductors, a cord and plug adapted for insertion in said jack for extending a calling con nection from said line, means for controlling said switch to establish a connection with said line, and common battery means for sup tilying current through said 'oicecurrent conductors to said line for talking purposes. i

51. In a telephone exchange system the combination of a subscribers telephone line, a spring; jack for said. line an automatic switch provided with voice-current con ductors, a cord and plug adapted for insertion in said jack for extending; a calling connection from said line means for controlling said switch to establish a connection with said line, common battery means for supplying current through said voice-current conductors to said line "for talking purposes and a common battery circuit including con tacts of said jack and plug.

52. In a telephone system, a plurality of subscribers lines divided into groupsmeans including an automatic connector switch having one motion to select groups and a second motion to find a called line in a selected group. and a busy test circuit includ 

